Alright, so this question is on my biology homework. I don't have the answer but I can tell you where to get it. Go to www.wlcsd.org there has to be the www or it doesn't work. Find the staff directory and look up lisa goff. Her website should be shown. Click on the link to her site and click on honors biology then online textbook. There should be a link to an online textbook the username and password which is case sensitive. The answer should be in chapter 6 section 6.1. Good luck!